No, I don't think you are necessarily gay, though I think everyone is on a continuum, no-one is 100% anything (possibly a controversial statement, but I'll leave that for others to discuss). What fantasy is about is thinking about things that are probably improbable or impossible for you, and the further they are from your actual life often the more of a turn-on they are. Your fantasy could have you being used by a blond businessman who comes into your executive hotel room, but instead you go to the other, more daring and exciting extreme and have it happen in a scummy motel with someone from a different social strata, different dress, etc.

As everyone here knows, the loss of power over your actions is the first step to allowing what appears to be daring to you, to happen. In this case you have given it more of an edge, as you know in reality you could stay in such a motel and even arrange for a male prostitute to act out such a scene, so whilst it has that dangerous, fantasy-like quality you have rooted it in the feasible as well. I guess all men have fantasies about having sex with other men at some time, in the way they also fantasise about sleeping with their sister-in-law, because it is taboo, so gives it an edge that might otherwise be missing.

What you do about it is up to you. You could write it down and masturbate over it a few times, and I am sure as your mind normalises it, it will become less of a thrill and you may then wonder what all the fuss was about and return to straight fantasies. You could watch a video of such a set-up. You could probably quite easily arrange to role play such a scene (I would not advise trolling round cheap motels looking for such an encounter, though many people would).

I think you need to explore what this fantasy means to you. I guess most likely your mind will tire of it and will move on to something such as the Oriental hostess on your flight or something of that nature. If you find that does not happen and you develop more fantasies on the same theme, this does not mean you are gay, you could just be straight with some bi curiosity or it might be a stronger element in your character. Women are told that they should only start worrying about their husband's sexual orientation if he has more than two gay flings. However, I think the first place is to write it out as you have done and then see how you feel about it as time passes. Often your body (and libido) knows what is really going on inside your mind more than your mind does.